System and methods for enhancing coexistence efficiency for multi-radio terminals

ABSTRACT

A method of scheduling transmitting and receiving communication slots for co-located radio devices is provided. A Bluetooth (BT) device first synchronizes its communication time slots with a co-located radio module, and then obtains the traffic pattern of the co-located radio module. Based on the traffic pattern, the BT device selectively skips one or more TX or RX time slots to avoid data transmission or reception in certain time slots and thereby reducing interference with the co-located radio module. In addition, the BT device generates a co-located coexistence (CLC) bitmap and transmits the CLC bitmap to its peer BT device such that the peer BT device can also skip data transmission or reception in certain time slots affected by the co-located radio module. The skipped time slots are disabled for TX or RX operation to prevent interference and to achieve more energy saving.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 from U.S.Provisional Application No. 61/254,771, entitled “Systems and Methodsfor Enhancing BT, LTE, and WiMAX Coexistence Efficiency,” filed on Oct.26, 2009, the subject matter of which is incorporated herein byreference.

TECHNICAL FIELD

The disclosed embodiments relate generally to wireless networkcommunications, and, more particularly, to Multi-Radio Terminals (MRT)containing Bluetooth (BT) and Mobile Wireless Systems (MWS) radios.

BACKGROUND

The Institute of Electrical and Electronics Engineers (IEEE) has adopteda series of standards for both wireless local area networks (WLANs)known as 802.11 and wireless metropolitan area networks (WMANs) known as802.16. It is commonly known that WiFi refers to interoperableimplementations of the IEEE 802.11 technology, and WiMAX (worldwideinteroperability for microwave access) refers to interoperableimplementations of the IEEE 802.16 technology. On the other hand,Bluetooth is a wireless standard for wireless personal area networks(WPANs) developed by the Bluetooth special interest group (SIG).Bluetooth provides a secure way for exchanging data over short distancesusing frequency-hopping spread spectrum technology. Due to scarce radiospectrum resource, different technologies may operate in overlapping oradjacent radio spectrums. For example, WiFi often operates at2.412-2.4835 GHz, WiMAX often operates at 2.3-2.4 or 2.496-2.690 GHz,and Bluetooth often operates at 2.402-2.480 GHz.

As the demand for wireless communication continues to increase, wirelesscommunication devices such as cellular telephones, personal digitalassistants (PDAs), laptop computers, etc., are increasingly beingequipped with multiple radios. A multiple radio terminal (MRT) maysimultaneously include Bluetooth, WiMAX, and WiFi radios. Simultaneousoperation of multiple radio modules co-located on the same physicaldevice, however, can suffer significant degradation includingsignificant interference between them because of the overlapping oradjacent radio spectrums. Due to physical proximity and radio powerleakage, when the transmission of data for a first radio module overlapswith the reception of data for a second radio module in time domain, thesecond radio module reception can suffer due to interference from thefirst radio module transmission. Likewise, data transmission of thesecond radio module can interfere with data reception of the first radiomodule.

FIG. 1 (Prior Art) is a diagram that illustrates interference between amobile wireless system (MWS) radio module 11 and a Bluetooth (BT) masterradio module 12 that are co-located in an MRT10. Both MWS11 and BT12transmit and receive data via scheduled transmitting (TX) and receiving(RX) time slots on a frame-by-frame basis. For example, each MWS framecontains five consecutive RX slots scheduled for receiving operationfollowed by three consecutive TX slots scheduled for transmittingoperation. On the other hand, a Time Division Duplex (TDD) scheme isused by BT devices where a BT master and a BT slave alternate TX and RXoperation. Because MWS radio module 11 and BT radio module 12 areco-located within MRT10, in a general, the transmission of one radiomodule will interfere with the reception of another radio module. Asillustrated in FIG. 1, data reception in three RX time slots of BT12 areinterfered by concurrent data transmission in TX time slots of MWS11,and data reception in six RX time slots of MWS11 are interfered byconcurrent data transmission in TX time slots of BT12.

FIG. 2 (Prior Art) is a diagram that illustrates traffic pattern of a BTmaster device 22 affected by a co-located MWS radio module 21. Thetraffic pattern of MWS21 remains the same as the traffic pattern ofMWS11 in FIG. 1, while BT22 has an Extended Voice (EV3) traffic patternusing an Extended Synchronous Connection Oriented (eSCO) link, withT_(eSCO)=6 and W_(eSCO)=4. Under such EV3 traffic pattern, BT22 has onescheduled TX time slot followed by one scheduled RX time slot for everysix BT slots (i.e., T_(eSCO)=6), with four retransmission opportunities(i.e., W_(eSCO)=4). In the example of FIG. 2, data transmission of MWS21interferes with data reception of BT22, while data transmission of BT22does not interfere with data reception of MWS21 (e.g., because of lowtransmission power of BT22). As a result, EV3 data reception in thescheduled EV3RX time slot in eSCO window #2 is corrupted, causing BT22to re-transmit EV3 data to a BT slave in the following EV3TX time slotand to receive EV3 data from the BT slave in the following EV3RX timeslot successfully. It can be seen that BT22 consumes 25% more energy dueto interference from co-located MWS21. A solution is sought to improveefficiency and save energy for radio modules co-located within the sameMRT.

SUMMARY

A method of scheduling transmitting and receiving communication slotsfor co-located radio devices is provided. A Bluetooth (BT) device firstsynchronizes its communication time slots with a co-located radiomodule, and then obtains the traffic pattern of the co-located radiomodule. The traffic pattern information includes frame configurationinformation such as DL/UL duration, active/inactive duration, and framelength. Based on the traffic pattern, the BT device selectively skipsone or more TX or RX time slots to avoid data transmission or receptionin certain time slots and thereby reducing interference with theco-located radio module. The skipped time slots are disabled for TX orRX operation to prevent interference and to achieve more energy saving.

In one embodiment, the BT device generates co-located coexistence (CLC)information based on the traffic pattern information. The CLCinformation may be represented by a CLC bitmap, each bit of the CLCbitmap indicates whether a communication slot can be used fortransmitting or receiving data. For example, in a TX CLC bitmap, eachbit indicates whether data transmission of a communication slot of theBT radio module will interfere with data reception of the co-locatedradio module in a corresponding time slot. Similarly, in a RX CLCbitmap, each bit indicates whether data transmission of the co-locatedradio module will interfere with data reception of the BT device in acorresponding time slot. The generated CLC bitmap is used forselectively skipping TX or RX operation to avoid interference. The BTdevice then transmits the CLC bitmap to its peer BT device such that thepeer BT device can also skip data transmission or reception in certaintime slots affected by the co-located radio module.

Other embodiments and advantages are described in the detaileddescription below. This summary does not purport to define theinvention. The invention is defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, where like numerals indicate like components,illustrate embodiments of the invention.

FIG. 1 (Prior Art) is a diagram that illustrates interference between aBT device and a co-located MWS radio module.

FIG. 2 (Prior Art) is a diagram that illustrates EV3 traffic pattern ofa BT device affected by interference from a co-located MWS.

FIG. 3 illustrates a simplified block diagram of a Multi-Ratio Terminal(MRT) having a MWS radio module and a BT device in a wirelesscommunication system in accordance with one novel aspect.

FIG. 4 illustrates a first embodiment of selectively skippingcommunication slots in accordance with one novel aspect.

FIG. 5 illustrates a second embodiment of selectively giving upcommunication slots in accordance with one novel aspect.

FIG. 6 illustrates a first example of CLC bitmap in accordance with onenovel aspect.

FIG. 7 illustrates a second example of CLC bitmap in accordance with onenovel aspect.

FIG. 8 illustrates the use of a CLC bitmap by a BT master device and aBT slave device.

FIG. 9 illustrates different examples of selectively giving up scheduledcommunication slots by a BT master and a BT slave device.

FIG. 10 illustrates the energy saving of a BT device with the proposedscheduling method.

FIG. 11 illustrates a deadlock problem resolved with the proposedscheduling method.

FIG. 12 illustrates a simplified block diagram of an MRT having anIEEE802.11-compatible device and a BT device in accordance with a novelaspect.

FIG. 13 is a flow chart of a method of scheduling TX and RXcommunication slots for co-located radio devices in accordance with onenovel aspect.

FIG. 14 is a flow chart of a method of generating CLC information forco-located radio devices in accordance with one novel aspect.

DETAILED DESCRIPTION

Reference will now be made in detail to some embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings.

FIG. 3 illustrates a simplified block diagram of a Multi-Ratio Terminal(MRT) 32 in a wireless communication system 30 in accordance with onenovel aspect. Wireless communication system 30 comprises a base stationBS31, a mobile station MRT32, and a BT headset BT33. Mobile stationMRT32 simultaneously includes a mobile wireless system (MWS) radiomodule 45 and a Bluetooth (BT) radio module 46. MRT32 communicates withits serving base station BS31 using MWS radio module 45 via a WiMAX link34, while communicates with a BT headset BT33 using BT radio module 46via a BT link 35. MWS radio module 45 comprises a transmitter and/orreceiver 41 and an MWS driver control block 42. BT radio module 46comprises a transmitter and/or receiver 43 and a BT driver control block44. MWS driver 42 and BT driver 44 communicate with each other via acoexistence-signaling interface 49. Coexistence-signaling interface 49is also connected to processor 47 and memory 48 of mobile station MRT32.Although coexistence signaling interface 49 is denoted as one module, itmay include both hardware and software implementation. For example,hardware implementation may be used for timing/synchronization betweenMWS45 and BT46, while software implementation may be used for trafficinformation exchange.

In the example of FIG. 3, MWS45 is a WiMAX radio module that operates at2.3-2.4 or 2.496-2.690 GHz, while BT46 is a BT radio module thatoperates at 2.402-2.480 GHz. Simultaneous operation of multiple radiomodules co-located on the same physical device, however, can suffersignificant degradation including significant interference between thembecause of the overlapping or adjacent radio spectrums. This isespecially true when both MWS45 and BT46 use time division multiplexing(TDM) protocol for data communication. Under TDM mode, when a scheduledcommunication time slot for data transmission for a first radio moduleoverlaps in time with a scheduled communication time slot for datareception for a second radio module, data reception of the second radiomodule can suffer due to interference from data transmission of thefirst radio module. Likewise, data transmission of the second radiomodule can interfere with data reception of the first radio module.

In one novel aspect, BT radio module 46 selectively skips scheduledtransmitting (TX) and/or receiving (RX) time slots to improve schedulingefficiency and thereby save energy via coexistence-signaling interface49. As illustrated in FIG. 3, BT46 first synchronizes its communicationtime slots with MWS45 (step 1), and then obtains the traffic pattern ofMWS45 (step 2) via coexistence-signaling interface 49. The trafficpattern information includes frame configuration information such asDL/UL duration and frame length. Based on the traffic pattern, BT46selectively skips one or more TX or RX time slots to avoid mutualinterference between BT46 and MWS45 (step 3). In addition, BT46generates a co-located coexistence (CLC) bitmap (step 4) and transmitsthe CLC bitmap to its peer BT device (step 5) such that the peer BTdevice can also skip data transmission or reception in certain timeslots affected by MWS45. During the skipped time slots, TX or RXoperation is given up by disabling or turning off the transmitter orreceiver to achieve more energy saving. Various embodiments and examplesare now described below with more details.

FIG. 4 illustrates a first embodiment of selectively skippingcommunication slots in accordance with one novel aspect. In the exampleof FIG. 4, MWS radio module 51 has a typical MWS traffic pattern, eachMWS frame contains eight communication slots including five consecutiveRX slots followed by three consecutive TX slots. On the other hand, BTmaster radio module 52 has an Asynchronous Connection-Oriented (ACL)traffic pattern. A Time Division Duplex (TDD) scheme is used by BTdevices where BT master and BT slave alternate TX and RX operation. Thepacket start shall be aligned with the slot start. BT master 52 firstaligns its communication slots with MWS51 to minimize mutualinterference. BT52 then obtains the traffic pattern of MWS51. Based onthe obtained traffic pattern, BT master 52 deliberately gives up certainallowed TX and RX slots that will be affected by co-located MWS radiomodule 51 to save energy. As illustrated in FIG. 4, the TX/RXcommunication slots denoted by a think-lined box are originally allowedfor TX and RX operation, but are now being selectively skipped becausethose slots will be affected by MWS51.

FIG. 5 illustrates a second embodiment of selectively skippingcommunication slots in accordance with one novel aspect. In the exampleof FIG. 5, MWS radio module 53 has the same traffic pattern as MWS51 inFIG. 4, each MWS frame contains eight communication slots including fiveconsecutive RX slots followed by three consecutive TX slots. BT masterradio module 54, however, has an extended voice (EV3) traffic pattern,each eSCO window contains six communication slots (i.e., T_(eSCO)=6)with one reserved TX slot followed by one reserved RX slot and fourretransmission time slots (i.e., W_(eSCO)=4). As illustrated in FIG. 5,BT54 deliberately gives up EV3 data transmission in originally reservedTX slot 55 because an acknowledgement for the transmitted EV3 data willnot be successfully received in the next RX slot 56 due to interferencefrom MWS53. In addition, BT54 also skips EV3 data reception inoriginally reserved RX slot 56 to save energy. Instead, BT54 performsdata transmission and reception successfully in the next TX slot 57 andRX slot 58 in eSCO window #2.

A further improvement can be achieved when a BT master informs a BTslave that the BT master cannot perform RX operation in certaincommunication slots. As a result, the BT slave can also avoid null EV3data transmission in these slots and thus save energy. As illustrate inFIG. 5, the BT slave is originally reserved to transmit EV3 data to BTmaster 54 in slot 56. Because the BT slave is informed that BT master 54cannot perform data reception in this slot, the BT slave thusdeliberately skips sending EV3 data in slot 56 to save energy.

From the above illustration, it can be seen that based on the trafficcharacteristics or traffic pattern of a co-located MWS radio module, aBT master and slave can selectively skip TX and RX slots to save energy.Because the traffic pattern for a co-located MWS radio module can beobtained by the BT device, such information can be shared between the BTmaster and slave to improve scheduling efficiency by avoiding affectedcommunication slots. Furthermore, because the traffic pattern of an MWSradio module is repeated for every MWS frame, such information can berepresented as a co-located coexistence (CLC) bitmap described below.

FIG. 6 illustrates a first example of CLC bitmap in accordance with onenovel aspect. In the example of FIG. 6, each MWS frame is 5 ms in lengthand contains eight communication slots including five RX slots followedby three TX slots. Each BT slot is 625 us in length. After framesynchronization, the MWS frames are aligned with BT slots in timedomain. If data transmission of the co-located MWS radio moduleinterferes with data reception of the BT device, then the BT device willnot perform data reception in any of the MWS TX slots. As illustrated inFIG. 6, a BT RX CLC bitmap 61 is used to indicate whether a BT slot canbe used to receive data. For example, a “1” bit indicates YES for datareception and a “0” bit indicates NO for data reception. Similarly, ifdata transmission of the BT device interferes with data reception of theco-located MWS radio module, then the BT device will not perform datatransmission in any of the MWS RX slots. As a result, a BT TX CLC bitmap62 in FIG. 6 is used to indicate whether a BT slot can be used totransmit data. Because every twenty-four BT slots are aligned with threeMWS frames and the traffic pattern of the MWS radio module repeats forevery frame, the 24-bit RX CLC bitmap 61 and TX CLC bitmap 62 aresufficient to represent packet scheduling information.

FIG. 7 illustrates a second example of CLC bitmap in accordance with onenovel aspect. The MWS frame and traffic pattern in FIG. 7 is the same asthe MWS frame and traffic pattern illustrated in FIG. 6. In the exampleof FIG. 7, however, data transmission of the BT device does notinterfere with data reception of the co-located MWS radio module. Thisis also referred to as hybrid mode, which normally occurs when thetransmission power of the BT device is relatively low. Under the hybridmode, BT RX CLC bitmap 71 in FIG. 7 remains the same as BT RX CLC bitmap61 in FIG. 6. BT TX CLC bitmap 72, however, contains only “1” bitsbecause every BT slot can be used to transmit data.

FIG. 8 illustrates the use of CLC bitmaps by a BT master device 81 and aBT slave device 82. An eSCO link with T_(eSCO)=6 and W_(eSCO)=4 existsbetween them. In the example of FIG. 8, BT master 81 is co-located withan MWS radio module 83. MWS83 has a typical traffic pattern asillustrated in FIG. 7. Based on the traffic pattern, BT master 81generates a BT RX CLC bitmap 84 and a BT TX CLC bitmap 85, both the sameas BT RX CLC bitmap 71 and BT TX CLC bitmap 72 illustrated in FIG. 7respectively. After the CLC bitmap information is generated by BT master81, it is then transmitted to BT slave 82 via a Link Manager Protocol(LMP) message (e.g., LMP_CLC_BITMAP). As illustrated in FIG. 8, both BTmaster 81 and slave 82 have an EV3 traffic pattern, with originallyscheduled EV3TX and EV3RX time slots at the beginning of each eSCOwindow. Based on the CLC bitmap information, BT master 81 skips thescheduled EV3 activity in slots 86 and 87. Similarly, BT slave 82 alsoskips the scheduled EV3 activity in slots 88 and 89. Instead, BT master81 and BT slave 82 performs EV3TX and EV3RX in the next twocommunication slots. As a result, data transmission and reception underthe adjusted EV3 traffic pattern of BT master 81 and BT slave 82 willnot be interfered by co-located MWS radio module 83.

FIG. 9 illustrates different examples of selectively skipping scheduledcommunication slots by a BT master and a peer BT slave device. The BTmaster is co-located with an MWS radio module having a typical WiMAXtraffic pattern depicted at the top of FIG. 9. Based on the WiMAXtraffic pattern, the BT master determines certain time slots that the BTmaster would not perform data transmission as denoted by area withslashed shading. Data transmission in these time slots would causeinterference to the co-located MWS radio module because they overlapwith the downlink receiving (DL RX) activity of the MWS radio module.Because the BT master would not perform data transmission in these timeslots, it also implies that the same time slots should not be used fordata reception by the peer BT slave. Similarly, the BT master determinescertain time slots that the BT master will not perform data reception asdenoted by areas with dotted shading. Data reception in these time slotswould be interfered by the co-located MWS radio module because theyoverlap with the uplink transmitting (UL TX) activity of the MWS radiomodule. Because the BT master would not perform data reception in thesetime slots, it also implies that the same time slots should not be usedfor data transmission by the peer BT slave.

In a first example #1, the BT master device selectively gives up one ormore scheduled TX slots if a corresponding acknowledgement (ACK) of thetransmitted data cannot be received successfully due to interference.For instance, the first time slot in eSCO window #2 (denoted by athink-lined box) is originally scheduled for data transmission for theBT master, but is now skipped because the BT master knows that it cannotsuccessfully receive an ACK for the transmitted data in the next slot.

In a second example #2, the BT slave device selectively gives up one ormore scheduled TX slots if it is estimated that the data to betransmitted would not be received by its peer BT device successfully.For instance, the second time slot in eSCO window #2 (denoted by athink-lined box) is originally scheduled for data transmission for theBT slave, but is now skipped because the BT slave is informed that itspeer BT master would not be able to receive the transmitted datasuccessfully.

In a third example #3, the BT master device selectively gives up one ormore scheduled TX slots if it is estimated that data transmission inthose TX slots would interfere data reception of the co-located device.For instance, the first time slot in eSCO window #3 (denoted by athink-lined box) is originally scheduled for data transmission for theBT master, but is now skipped because the BT master knows that thetransmitting operation would cause RX failure on the co-located MWSradio module.

In a fourth example #4, the BT master device selectively gives up one ormore scheduled RX slots if the receiving operation would be affected byinterference from the co-located MWS radio module. For instance, thesecond time slot in eSCO window #2 (denoted by a think-lined box) isoriginally scheduled for data reception for the BT master, but is nowskipped because the BT master knows that it cannot successfullyreceiving data due to interference from the co-located MWS radio module.

In a fifth example #5, the BT slave device selectively gives up one ormore scheduled RX slots if it is estimated that its peer BT device wouldnot transmit data in those RX slots. For instance, the first time slotin eSCO window #3 (denoted by a think-lined box) is originally scheduledfor data reception for the BT slave, but is now skipped because the BTslave is informed that its peer BT master would not transmit data inthis slot.

FIG. 10 illustrates the energy saving of a BT master and slave with theproposed scheduling method. The top half of FIG. 10 illustrates WiMAXand BT activity with conventional eSCO solution using EV3 (T_(eSCO)=6,and W_(eSCO)=4). Under conventional scheduling, if a scheduled TX or RXslot fails because of interference, then the BT master and slaveperforms retransmission in the next available slots. Based on thewaveforms of BT master TX, BT master RX, BT slave TX, and BT slave RX,the duty cycle of the BT master and BT slave can be calculated as:D _(MASTER)=(10×382 μs+4×90 μs)/15 ms=27.9%D _(SLAVE)=(10×382 μs+2×126 μs+6×90 μs)/15 ms=30.7%

The bottom half of FIG. 10 illustrates WiMAX and BT activity withproposed eSCO solution using EV3 (T_(eSCO)=6, and W_(eSCO)=4). Under theproposed scheduling, if a scheduled TX or RX is estimated to failbecause of interference, then the BT master and slave skip the scheduledslot and perform TX or RX in the next available slots. Because theskipped slot is given up for TX or RX operation, the transmitter orreceiver is disabled or turned off during the skipped slot to saveenergy. Based on the waveforms of BT master TX, BT master RX, BT slaveTX, and BT slave RX, the duty cycle of the BT master and BT slave can becalculated as:D _(MASTER)=(8×382 μs+126 μs)/15 ms=21.2%D _(SLAVE)=(8×382 μs+2×90 μs+126 μs)/15 ms=22.4%Thus, the proposed method for eSCO scheduling saves (27.9−21.2)/27.9≈24% energy for BT master, and saves (30.7 −22.4)/30.7≈27%for BT slave.

FIG. 11 illustrates a deadlock problem and a solution under the proposedscheduling method. In the example of FIG. 11, a BT master communicateswith a BT slave, and the BT slave is co-located with an MWS radio modulehaving typical WiMAX traffic pattern. The communication slots markedwith MNA and MA are TX slots for the BT master polling with NACK or ACK.The communication slots marked with SD and S are TX slots for the BTslave with or without sending data. The top half of FIG. 11 illustratesa deadlock problem under conventional packet scheduling method. When theBT slave transmits data in a first SD slot 111, the BT master transmitsan ACK to acknowledge the transmitted data in the next corresponding MAslot 112. The ACK transmitted by the BT master, however, is corrupteddue to interference from data transmission of the MWS radio module. Nexttime when the BT master transmits, it changes from ACK to NACK underAutomatic Retransmission Request (ARQ) mechanism. Because the BT slavehas never received an ACK for its transmitted data in slot 111, itattempts to retransmit the same data packet in the next SD slot 113. TheBT master again transmits an ACK to the BT slave in the next MA slot114. The ACK is again corrupted due to interference from the co-locatedMWS radio module. The same operation repeats thus deadlock forms.

The bottom half of FIG. 11 illustrates how the above-described deadlockproblem is resolved by the proposed scheduling method. After the BTmaster receives data transmitted from the BT slave in the first SD slot111, the BT master skips its next scheduled TX slot 112 for sending theACK to the BT slave. This is because the BT master is informed by the BTslave that the BT slave cannot successfully receive data in slot 112 dueto interference from the co-located MWS radio module. Instead, the BTmaster postpones the ACK transmission to the next TX slot 115, and theACK is successfully received by the BT slave without interference fromthe MWS radio module. Thus, by deliberately giving up certain scheduledTX/RX slots, the scheduling deadlock problem is resolved.

FIG. 12 illustrates a simplified block diagram of a MRT 120 having anIEEE802.11-compatible device Wi-Fi121 and a BT device BT122 inaccordance with a novel aspect. Wi-Fi121 comprises a transmitter and/orreceiver 123 and a Wi-Fi driver 124. BT radio module 122 comprises atransmitter and/or receiver 125 and a BT driver 126. Wi-Fi driver 124and BT driver 126 communicate with each other via acoexistence-signaling interface 129. Coexistence-signaling interface 129is also connected to processor 127 and memory 128 of MRT120. In theexample of FIG. 12, Wi-Fi121 is a Wi-Fi radio module that operates at2.412-2.4835 GHz, while BT122 is a BT radio module that operates at2.402-2.480 GHz. Simultaneous operation of multiple radio modulesco-located on the same physical device, however, can suffer significantdegradation including significant interference between them because ofthe overlapping or adjacent radio spectrums. Thus, scheduling thetransmission and reception of the co-located radio modules not tooverlap in time domain can substantially reduce the interference betweenthem and thereby increase system performance.

In one novel aspect, BT radio module 122 generates a CLC bitmap to beshared between Wi-Fi radio module 121 for packet scheduling such thatthe transmission and reception of the two radio modules do not overlapin time domain. As illustrated in FIG. 12, BT122 first receives a CLCrequest from Wi-Fi121 (step 1), and then obtains traffic characteristicsand requirement, such as Wi-Fi121 requests to use 50% of the time, fromWi-Fi121 (step 2) via coexistence-signaling interface 129. Based on thetraffic characteristics and requirement, BT122 generates a co-locatedcoexistence (CLC) bitmap and transmits the CLC bitmap back to Wi-Fi121(step 3). For example, BT CLC bitmap 130 in FIG. 12 indicates a numberof pre-defined communication slots reserved by BT122 to perform datatransmission and reception. BT CLC bitmap 130 also indicates a timeduration when BT122 does not perform any TX or RX operation. In oneembodiment, BT122 transmits a countdown signal to WiFI121 (step 4).Based on the CLC bitmap and the countdown signal, WiFi121 enters activemode when BT122 does not perform TX or RX operation, and enterspower-saving mode during the reserved communication slots to reduceinterference. In addition, BT122 transmits CLC bitmap 130 to its peer BTdevice (step 5) such that the peer BT device performs TX or RX operationonly during the reserved time slots.

FIG. 13 is a flow chart of a method of scheduling TX and RXcommunication slots for co-located radio devices in accordance with onenovel aspect. In step 131, a BT radio module obtains traffic patterninformation of another co-located radio module. In step 132, the BTradio module schedules its communication slots for TX and RX operation.The communication time slots of the BT radio module and the other radiomodule are aligned after frame synchronization. In step 133, the BTradio module selectively skips one or more TX and/or RX time slots basedon the obtained traffic pattern information to avoid interferencebetween the BT radio module and the co-located radio module. Instead,the BT radio module performs TX and RX operation during the time slotsthat are not affected by the co-located radio module. By deliberatelygiving up TX or RX time slots and disabling TX or RX operation duringthe skipped time slots, better scheduling efficiency and more energysaving is achieved for the BT radio module.

FIG. 14 is a flow chart of a method of generating CLC information forco-located radio devices in accordance with one novel aspect. In step141, a BT radio module obtains traffic pattern information of aco-located radio module. In step 142, the BT radio module determines CLCinformation based on the traffic pattern information. The CLCinformation indicates whether one or more communication slots of the BTradio module can be used for TX or RX operation. In step 143, the BTradio module transmits the CLC information to its peer BT module suchthat the peer BT can more efficiently schedule its TX and RX operationand thereby save more energy.

Although the present invention has been described in connection withcertain specific embodiments for instructional purposes, the presentinvention is not limited thereto. For example, although a WiMAX radiomodule and a Wi-Fi radio module are used in the detailed description, aLong Term Evolution (LTE) device may be used as a co-located radiomodule instead. In addition, the BT device co-located with another radiomodule may be either a BT master or a BT slave. Accordingly, variousmodifications, adaptations, and combinations of various features of thedescribed embodiments can be practiced without departing from the scopeof the invention as set forth in the claims.

What is claimed is:
 1. A method comprising: obtaining traffic pattern information of a first plurality of communication slots of a first radio module; scheduling a second plurality of communication slots for transmitting (TX) or receiving (RX) operation of a second radio module, wherein the second plurality of communication slots is aligned with the first plurality of communication slots, and wherein the second radio module and the first radio module are co-located within a wireless communication device; selectively skipping one or more communication slots from the second plurality of communication slots based at least in part on the traffic pattern information, wherein the skipped slots are disabled for TX or RX operation.
 2. The method of claim 1, wherein a transmit slot is skipped when an acknowledgement is estimated not to be received successfully in a corresponding receive slot due to interference from the first radio module.
 3. The method of claim 1, wherein a transmit slot is skipped when data transmission performed in the transmit slot is estimated to interfere with data reception of the first radio module.
 4. The method of claim 1, wherein a receive slot is skipped when data reception performed in the receive slot is estimated to be interfered by data transmission of the first radio module.
 5. The method of claim 1, further comprising: determining Co-located Coexistence (CLC) information based at least in part on the traffic pattern information by the second radio module; and transmitting the CLC information to a peer radio module by the second radio module.
 6. The method of claim 5, wherein one or more communication time slots is skipped to prevent from scheduling deadlock between the second radio module and the peer radio module.
 7. The method of claim 5, wherein a transmit slot of the peer radio device is skipped when data transmitted in the transmit slot is estimated not to be received successfully by the second radio module due to interference from the first radio module.
 8. The method of claim 5, wherein a receive slot of the peer radio device is skipped when the second radio module is estimated not to transmit any data in a corresponding transmit slot.
 9. A wireless communication device, comprising: a first radio module comprising a first radio frequency (RF) transceiver that schedules a first plurality of communication slots for transmitting (TX) or receiving (RX) operation; and a co-located second radio module, comprising: a second RF transceiver that schedules a second plurality of communication slots for TX or RX operation, wherein the second plurality of slots is aligned with the first plurality of communication slots; and a driver control block that selectively skips one or more communication slots based at least in part on traffic pattern information of the first plurality of communication slots.
 10. The wireless communication device of claim 9, wherein the wireless communication device is a Multi-Radio Terminal (MRT), wherein the first radio module is a Mobile Wireless Systems (MWS) radio module, and wherein the second radio module is a Bluetooth (BT) radio module.
 11. The wireless communication device of claim 9, wherein the one or more communication slots of the second radio module are skipped to avoid interference between the first radio module and the second radio module.
 12. The wireless communication device of claim 9, wherein the driver control block determines Co-located Coexistence (CLC) information based at least in part on the traffic pattern information, and wherein the second radio module transmits the CLC information to a peer radio module.
 13. The wireless communication device of claim 12, wherein the one or more communication slots of the BT radio module is skipped to avoid scheduling deadlock between the BT radio module and the peer radio module.
 14. The wireless communication device of claim 12, wherein the CLC information is represented by a CLC bitmap, each bit indicating whether an operation of a communication slot of the second radio module will be affected due to interference between the first radio module and the second radio module.
 15. The wireless communication device of claim 12, wherein one or more communication slots of the peer radio module is selectively skipped based on the CLC information.
 16. A method comprising: obtaining traffic characteristics of a first radio module by a Bluetooth (BT) radio module, wherein the first radio module is a mobile wireless system (MWS) module, and wherein the first radio module and the BT radio module are co-located within a Multi-Radio Terminal (MRT); determining Co-located Coexistence (CLC) information based at least in part on the traffic characteristics, wherein the CLC information indicates whether the BT radio module and the first radio module is estimated to interfere with each other in one or more communication slots, and wherein the BT radio module selectively skips one or more communication slots based on the CLC information; and transmitting the CLC information to a peer BT radio module.
 17. The method of claim 16, wherein one or more communication slots of the peer BT radio module is selectively skipped based on the CLC information.
 18. The method of claim 16, wherein the CLC information is represented by a CLC bitmap, each bit indicating whether an operation of the BT radio module and the MWS radio module will interfere with each other in a corresponding communication slot.
 19. The method of claim 18, wherein the CLC bitmap is a transmit (TX) CLC bitmap, each bit indicating whether data transmission of the BT radio module will interfere with data reception of the MWS radio module in a corresponding communication slot.
 20. The method of claim 18, wherein the CLC bitmap is a receive (RX) CLC bitmap, each bit indicating whether data reception of the BT radio module will be interfered by data transmission of the MWS radio module in a corresponding communication slot.
 21. The method of claim 16, wherein the first radio module is an IEEE802.11-compatible radio module, and wherein the BT radio module receives a request to generating the CLC information.
 22. The method of claim 21, wherein the CLC information indicates pre-defined communication slots reserved by the BT radio module.
 23. The method of claim 22, wherein the CLC information is transmitted to the first radio module such that the first radio module enters power-saving mode during the reserved communication slots.
 24. The method of claim 22, wherein a countdown time is transmitted to the first radio module such that the first radio module enters power-saving mode during the reserved communication slots.
 25. An apparatus, comprising: a radio frequency (RF) transceiver that schedules a first plurality of communication slots for transmitting (TX) or receiving (RX) operation, wherein the first plurality of slots is aligned with a second plurality of communication slots of a co-located radio module; and a driver control block that selectively skips one or more communication slots based at least in part on traffic pattern information of the co-located radio module, and wherein TX or RX operation is disabled for the skipped communication slots.
 26. The apparatus of claim 25, wherein the one or more communication slots are skipped to avoid interference with the co-located radio module.
 27. The apparatus of claim 25, wherein the driver control block determines Co-located Coexistence (CLC) information based at least in part on the traffic pattern information, wherein the CLC information indicates whether the first plurality of communication slots can be used for TX or RX operation. 